The invention relates to a dental implant.
Known from EP 0 707 835 B1 is such a dental implant that is embodied in two phases and has an implant body that can be anchored in the jawbone and a structural part that can be jointed thereto by means of a tension screw. The implant body contains a central receiving opening that has a conical inner surface opening to the coronal end and furthermore has in the inner end area an inner thread for anchoring the tension screw. The structural part contains a through-hole through which the tension screw passes, whereby in a head area of the structural part that faces the oral cavity the through-hole has an expansion for receiving a head of the aforesaid tension screw. The structural part furthermore contains a pin that engages at least partially in the receiving opening and that has a conical outer surface that matches the conical inner surface of the receiving opening. The aforesaid conical surfaces are advantageously embodied such that there is a self-locking cone connection between the implant body and the structural part joined by means of the tension screw. This positive-fit and form-fit conical connection ensures that the structural part is lastingly secure against rotation of the structural part with respect to the implant body, whereby functionally-secure tension is provided and/or ensured by means of the tension screw. Moreover, the gap-free and play-free conical connection reliably prevents bacteria and other pathogens from penetrating into the interior of the dental implant. For placing the implant body into an appropriately prepared opening or bore in the jawbone, the implant body contains in its coronal area or the coronal end surface placement elements for a placement tool, such as for instance occlusally opening slits for a screwdriver. In this two-phase dental implant, the structural part can be positioned steplessly with the implant body in terms of the longitudinal axis so that in particular special measures are necessary when impressions required for fashioning the superstructure and/or in the dental laboratory in order to maintain conformal alignment of the structural part relative to the implant body.
Furthermore, known from DE 94 17 182 U1 is an implant kit intended for tooth replacement, the implant body of which, when connected to the conical inner surface, has an indexing element embodied as a polygonal receiving element. Analogously, the structural part also contains, as an indexing element, a polygonal element in the axial direction adjacent to the conical outer surface. The conical inner surface is disposed inside a head part of the implant body, the aforesaid head part having an outer surface that expands conically toward the coronal end surface of the implant body. The indexing elements are disposed in an area in which the implant body does not have a thread on the outside. The implant body does not have an outer thread for anchoring in the jawbone until it is spaced axially from the indexing elements, and the outer thread extends from approximately the center of the longitudinal extension of the implant body to its apical end. Since the indexing elements are provided axially adjacent to the conical inner surface of the implant body, the conical inner surface of the implant body extends only across a small part of its entire length so that only a quite small and axially short connecting surface is available for the cone connection to the structural part.
Moreover, known from DE 299 20 283 U1 is an implant kit, the structural part of which, or where necessary a separate spacing element, can be fixed in the implant body in a rotationally stable manner via a cone connection and a central fixing screw or tension screw. The structural part is provided with a plurality of female molds in which a male mold of the implant body engages, in a rotationally stabilizing manner, as an indexing element in order to assure the structural position. The male mold pin is disposed in an axial area of the implant body in which the latter does not have a outer thread. In addition, the aforesaid area has only a short axial length in comparison to the entire length of the implant body, specifically largely in the quite short head area of the implant body. The aforesaid male mold pin is an additional component that projects radially from outside through the implant body into the area of the cone connection, whereby a not insignificant degree of complexity is required for precise arrangement and alignment.
Finally, known from DE 101 29 684 A1 is a structural part, called a tooth or jaw segment, on a base support or implant body. For joining the structural part to the implant body, an additional connecting element embodied as a double cone is provided that is inserted on the one hand into a conical recess of the structural part and on the other hand into a conical recess of the implant body. The double-cone connecting element has a positive-fit element corresponding to the implant body, whereby however the angle of rotation position of the structural part can be freely specified with regard to the double-cone connecting part. Conforming alignment of the structural part to the implant body is not possible.
The underlying object of the invention is therefore to further develop the dental implant of the aforesaid type having low structural complexity and/or structural volume such that in terms of the longitudinal axis a defined alignment, hereinafter referred to as indexing, of the structural part with respect to the implant body can be specified. The interactions and advantages for the aforesaid cone connection should also be retained. It should be possible to dimension and embody the dental implant according to the specific requirements in the different functional areas, such as in particular cone connection, indexing, thread connection. In addition, disadvantageous effects that various functional areas have on one another and in particular with respect to an outer thread should be avoided and the requirements in terms of loadability and/or service life should be lastingly satisfied to a large degree. Moreover, an uncomplicated implant system should be created that enables selectively on the one hand stepless adjustment of the rotation position or on the other hand a defined specification of the rotation position of the structural part with respect to the implant body.